The use of so-called safety glazing or penetration resistant glazing for windows, windshields and the like utilizing polycarbonate resin layers as a structural component is well known. For example, glass polycarbonate resin laminates are described in U.S. Pat. No. 3,666,614, the glass and polycarbonate being cohered together using an ethylene-vinyl acetate copolymer. In U.S. Pat. No. 3,520,768, there are described laminates of relatively thick glass having a comparatively thin polycarbonate foil as the cohering material. It is also known to utilize certain polysiloxane polycarbonate block copolymers described more particularly hereinafter as the adhesive layers.
However, due to the difficulty of bonding glass to other materials generally, and polycarbonate resin specifically, in many cases, it has not previously been possible to provide entirely satisfactory glass-polycarbonate laminates which contain the requisite degree of clarity and will not delaminate under actual use conditions, particularly upon exposure to weather and high humidity. The identification of a proper adhesive for bonding glass to polycarbonate resins to produce laminates useful as glazing presents a particularly difficult problem since the bonding agent must not detract from the optical clarity of the glass-polycarbonate laminate; must durably bond glass and the polycarbonate; and must not deleteriously affect the polycarbonate, i.e., must be compatible with the polycarbonate.
The present invention provides a glass-polycarbonate laminate wherein the laminate has good optical properties, the glass is tightly and durably bonded to the polycarbonate, and the bonding agent is compatible with the polycarbonate.